Improved concrete pavement



UNITED STATES yPATENT OFFICE.

A. vAN CAMP, VOF WASHINGTON, DISTRICT OF COLUMBIA, AssIeNOR TO HIMSELF AND M; M. HODCIIMAN, On ST. LOUIS, MISSOURI.

IM PRVED CONCRETE PAVEMENT.

Specication forming partvof Letters Patent No. 93,142, dated July 27,1869.

To all whom it may concern:

Be it known thatl I, A. VAN CAMP, of Washington city, in the county' of Washington, and District of Columbia, have invented certain new and useful Improvements in Goncrete Pavements 5 and I do hereby declare that the following is a full,clear, and exact description of the same, reference being had to the accompanying drawings and to the letters of reference marked thereon, making part of this specification, in which- Figure l isa top view of the metal-lic mold or capsometimes used.y *Fig 2 is a side view of the same.

I am aware that many experiments hav been essayed having in view thev producing of a durable concrete pavement; one that would be enabled alike to resist the action ofthe frost and rain and the heat of the sun without cracking or otherwise being injured. Still, notwithstanding the numerous attempts that have been made, scarcely in a single instance has a pavement ot' this nature been introduced that in any degree meets with popular favor. Many reasons might be assigned for the failure of all this class of pavements, the chief of which is that when the pavement has been vused for a while it is found that a per mauent concretion of the mass has not taken place, which difficulty principally arises from the fact that the gravel, bowlders, or pebbles used, and which invariably constitute a prominent feature in all pavements of this character, soon work loose, Owing to the fact that their smooth and even surfacesy afford no resisting bearing for the cement or other material to embed itself in. In my improvement this difliculty is entirely remedied, and simply by crushing or pulverizing the rock, gravel, pebbles, or bowlders used before mixing the same with any other ingredient. The result is that instead ol a smooth'I I have a rough and uneven surface, which, after having been once embedded in the asphaltum or the residuum or pitch of coal-tar, which is the other ingredient I use, it is impossible for any of the particles to work loose or become disintegrated. have fully attested the fact that in attempting to break a block or section of this pavement the pieces of crushed gravel or stone are Indeed, n-umerous experiments' always broken in two, aud never in the slightest degree loosened in their sockets or bearings. f

To enable others skilled in the art to make and luse my invention, I will now proceed to describe its construction and operation.

I take any rock, bowlder, gravel, or pebble suited to the purpose, and crush or pulverize the same by any suitable and convenient means until they are reduced to,'compara` tively speaking, small particles. rIhis crushing or pulverizing process should be continued until the even or naturally smooth sur- These ingredients are placed in a large i open pau or vessel and subjected to a heat of l from 1200 to 1300, care being taken that the mass is stirred or agitated during the entire time that it is subjected to the lire, So soon as the ingredients are thoroughly mixed the composition is emptied into a suitable cart or Wagon and conveyed to the point or place where the same is to be used. It is then dumped out and spread, and properlyV laid by the aid of hot rollers.v For ordinary pavements the depth may be about two (2) inches; for prominent and much-traveled thoroughfares, about four (4) inches. pecially Whenthe composition is intended to be used for rooting purposes, sharp sand 'may be advantageously added.

Along railroad-tracks and in the immediate vicinity of points where the frequent removal for the purpose of repair, te., of the pavement is required, I propose to lay blocks prepared from the same composition. These blocks are prepared as follows: I place a number of open metallic molds, A, of the form shown in the drawng,'alonga hard smooth surface. These moldsI partially ll with the composition while the same is in a hot plastic Sometimes, es-

state, and then 4thoroughly ram with hot tamps or other suitable implement; then add more of the composition and repeat the ramming process. This is continued until the moldsmare filled, when the heated rollers are used1A Thefblocks are'then allowed to `cool, when, if the `molds have been `properly sandedbefore, they can be readily removed.

It will be seen by reference to Fig. 2 in the drawing that the mold A lis formed with tapering ends or sides. The blocks, of course,

y are of the same form and outline; thereforeV when they areplaced side byside their upper surfaces will be close together, but between each two blocks are angular recesses. Now?" when these blocks are laidin sand' thelsand gradually works up and fills this entire recess, and the blocks uniting on the WelLknown principle ofthe arch, a strong and ldurable pavement is `formed. If desired, the `blocks need `not beremoved from the molds, but the pavement laid with theblocks firmly cemented in ythe molds; 'When this plan is resorted to of course the molds should not be sanded before the composition is poured in,-as it is def sirable thatthe same should adhere in the most permanent manner to the sides of the mold# Havingthns fully described my invention, what I claim therein asnew, and desire to se- I Y y .3. Formingthe blocks in themetallic molds AL when the same are of the formistated and are laid with or without the molds-1 in sand,

substantially as described, as and lforl the pur-` pose specied. A l

p 4.` LayingV the concrete pavement when the same is composed of crushed rocker gravel and asphalt-um, by means of hot rollers, substantially as described. In testimony whereof I have signed my name to this specification in the presence of two Vsubscribing witnesses. l A. VAN OAMI.

Witnesses:

EDWIN JAMES,

JonN S. HoLLINGsHEAn. 

